Currently, a non-aqueous electrolyte secondary battery including a lithium ion secondary battery that is utilized for a mobile device such as a mobile phone is available as a commercial product. The non-aqueous electrolyte secondary battery generally has a constitution that a positive electrode having a positive electrode active material and the like coated on a current collector and a negative electrode having a negative electrode active material and the like coated on a current collector are connected to each other via an electrolyte layer in which a non-aqueous electrolyte solution or a non-electrolyte gel is held in a separator. The charge and discharge reactions of a battery occur as the ions such as lithium ions are absorbed into and desorbed from an electrode active material.
In recent years it has been desired to reduce the amount of carbon dioxide in order to cope with the global warming. Hence, a non-aqueous electrolyte secondary battery having a small environmental burden has been utilized not only in a mobile device but also in a power source device of electric vehicles such as a hybrid vehicle (HEV), an electric vehicle (EV), and a fuel cell vehicle.
As the non-aqueous electrolyte secondary battery for application to the electric vehicles, it is required to have a high output and a high capacity. Hence, intensive research and development have been underway in order to develop a technology which satisfies such performances. For example, a means for solving the problem that the discharge capacity decreases particularly at the time of high output (or high current) discharge when the film thickness of the electrode active material is at a certain degree or more in the case of using a powdered electrode active material is provided in JP-A-H07-122262. Specifically, the above problem is solved by setting the specific surface area of the electrode in the non-aqueous electrolyte secondary battery to 4 m2/g or more in JP-A-H07-122262. Incidentally, it is discussed in JP-A-H07-122262 that voids in the electrode increases as the specific surface area is set to 4 m2/g or more, and a decrease in discharge capacity even under a high output condition is prevented as the ionic conduction is secured.